This invention is generally directed to photoresponsive imaging members, and more specifically to polysilylene ceramers, which cermaers function as hole transporting substance, or may be selected as an overcoating for layered imaging members as illustrated, for example, in U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference. More specifically, there is provided in accordance with the present invention layered photoresponsive imaging members comprised of a ceramer, reference ACS Polymer Reprints 26 (2), 300, (1985), the disclosure of which is totally incorporated herein by reference, and an organic polysilylene hole transporting layer; and a photogenerating layer. Moreover, there is provided in one particular aspect of the present invention an improved layered photoresponsive imaging member comprised of a supporting substrate, a photogenerating layer and in contact therewith a hole transport layer comprised of a polysilylene ceramer component, particularly wherein the polysilylene is poly(methylphenyl silylene), poly(m-propylmethyl silylene), and other similar silylenes. The aforesaid hole, or charge transport components can be prepared generally by the hydrolysis reaction of silanol terminated polysilylene oligomers, or preferably slaol terminated silanol groups containing polysilyenes with tetraalkoxy silane to provide polysilylene segments wherein n is a number, for example, equal to or greater than 10 as illustrated herein, crosslinked through SiO.sub.4 units, which components are flexible and resistant to chemicals and physical abrasions such as scratching. The aforementioned polysilylene-ceramer component layer can be located as the top layer of the imaging member, or alternatively it may be situated between the supporting substrate, and the photogenerating layer. Moreover, the present invention is directed to the selection of the improved imaging members disclosed herein in electrophotographic, and especially xerographic imaging procesess inclusive of those wherein there is selected for development liquid ink compositions.
Additionally, there are provided in accordance with the present invention imaging members comprised of polysilylenes ceramers, which members contain thereover protective coatings primarily for the purpose of substantially eliminating or minimizing abrasion of the imaging member especially the photogenerating layer, which abrasion adversely effects image quality for example. Overcoatings generally in a thickness of, for example, from about 0.1 to about 2 microns that can be selected include those as illustrated, for example, in U.S. Pat. Nos. 4,565,760 and 4,595,602, the disclosures of which are totally incorporated herein by reference, polyesters, polyurethanes, and the like.
Numerous photoresponsive imaging members are known, inclusive of those wherein there are selected polysilylenes as hole transporting components, reference U.S. Pat. No. 4,618,551, the disclosure of which is totally incorporated herein by reference. More specifically, there is illustrated in the aforementioned patent a photoresponsive imaging member comprised of a supporting substrate, a photogenerating layer, and as a hole transport layer a polysilylene compound of the formula, for example, as recited in claim 1 wherein the substituents R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are independently selected from a group consisting of alkyl, aryl, substituted alkyl, substituted aryl and alkoxy, and n, m and p numbers that represent the percentage of the monomer unit and the total polymer compound. Furthermore, the selection of silicone resin overcoatings for the aforementioned members is illustrated in column 12 of this patent.
In addition, ceramers are known, reference for example American Chemical Society Polymer Prints 26, (2), page 300, (1985) Wilkesorle and Haune. There is indicated in this publication, the disclosure of which is totally incorporated herein by reference, that ceramers are ceramic like materials which incorporate polymer-oligomeric components directly into the network thereof. Accordingly, the aforementioned hybrid material ceramer includes a glass component in an amount of 40 percent or more of the resulting material with the remainder being an oligomeric, or polymeric substance.
Also, there is disclosed in U.S. Pat. No. 4,544,729 a photosensitive polymer comprised of a combination of silyl and siloxy moieties; while U.S. Pat. No. 4,356,246 discloses electrophotographic amorphous silicon materials wherein there can be physically combined a polysilane with a silicone resin, reference columns 2 and 8. The incorporation of other active compounds to convert a silicone resin film to a transport layer is illustrated in U.S. Pat. Nos. 4,278,746; 4,281,054; 4,429,029; 4,556,622 and 4,567,125.
Although the above described imaging members, particularly those disclosed in the aforementioned U.S. Pat. No. 4,618,551 and U.S. Pat. No. 4,265,660 are useful for their intended purposes, there is a need for improved imaging members. More specifically, there is a need for photoresponsive imaging members wherein undesirable charge traps are avoided and/or substantially eliminated thereby enabling members wherein unacceptably high residual potentials are avoided after photodischarge permitting images of excellent resolution with no background deposits for extended time periods. There is also a need for imaging members wherein there is selected polysilylene-ceramer components as the hole or charge transporting component, which materials are substantially inert to the users of these members. Further, there continues to be a need for improved photoresponsive imaging members which can be prepared with a minimum number of processing steps, and wherein the layers are sufficiently adhered to one another to permit the continuing use of these members in repetitive imaging processes. Also, there is a need for new hole transporting polysilylene ceramer compounds that are useful as protective overcoating layers and as in interface materials for various imaging members. Moreover, there continues to be a need for a specific layered imaging member which not only generates acceptable images but which can be repeatedly used in a number of imaging cycles without deterioration thereof in the machine environment or surrounding conditions while simultaneously preventing unacceptable high residual potentials to generate after photodischarge, and thereby adversely affecting image resolution. Likewise, there is a need for hole transporting compounds with increased stability, for example, wherein there is no extraction of these compounds from the layered imaging members in which they are incorporated when, for example, liquid developers are selected for rendering the latent electrostatic image visible. Furthermore, there is a need for hole transporting compounds useful in layered imaging members, which compounds are insulators in the dark compared to many other known hole transporting compounds thus enabling charging of the resulting imaging member to higher fields while maintaining cyclic stability and allowing improved developability. In addition, there is a need for enabling the preparation of imaging members with hole transporting compounds wherein the preparation sequence permits the selection of a variety of solvents inclusive of toluene, benzene, tetrahydrofuran, cyclohexane and halogenated solvents in addition to methylene chloride. Another need of the present invention resides in abrasion resistant imaging members that maintain their flexibility for extended time periods, and that retain their electrical properties for a substantially unlimited number of imaging cycles. There is also a need for layered imaging members wherein there is selected a protective overcoating, especially when the charge transport layer is situated between a supporting substrate and a photogenerating layer.